Lead sensor and methods of use

Abstract

A fluorophore that forms a complex with Pb ions is disclosed. The fluorophore/lead complex fluoresces with an intensity greater than complexes formed by the fluorophore with other metals. The fluorophore may be used as a sensor/detector for lead ions in various samples. Methods for detecting and calculating the concentration of lead ions in samples are also disclosed.

1. A fluorescent binder for Pb 2+  ions represented in its protected form by Formula IV: 
       
         
           
           
               
               
           
         
       
     
     
       2. The fluorescent binder of  claim 1 , wherein the binder has a sensitivity for Pb 2+  with a K d  of less than 500 nM. 
     
     
       3. The fluorescent binder of  claim 1 , wherein the Pb 2+  and the fluorescent binder form a Pb 2+ /binder complex. 
     
     
       4. The fluorescent binder of  claim 3 , wherein the Pb 2+ /binder complex has an excitation band centered around 389 nm and a fluorescence emission band centered around 423 nm. 
     
     
       5. The fluorescent binder of  claim 3 , wherein the Pb 2+ /binder complex fluoresces with a high fluorescence emission intensity at a pH value of 10 or less. 
     
     
       6. The fluorescent binder of  claim 3 , wherein the binder selectively binds to Pb 2+  over other metal ions. 
     
     
       7. The fluorescent binder of  claim 6 , wherein the other metal ions are selected from the group consisting of Li + , Na + , K + , Ca 2+ , Mg 2+ , Fe 2+ , Co 2+ , Ni 2+ , Cu 2+ , Zn 2+ ,Cd 2+ , Mn 2+ , Hg 2+ , As 3+ , and mixtures thereof. 
     
     
       8. The fluorescent binder of  claim 3 , wherein the fluorescence emission intensity of the Pb 2+ /binder complex is greater than a fluorescence emission intensity of other metal/binder complexes. 
     
     
       9. A Pb 2+  sensor comprising:
 a matrix material; and 
 a fluorophore represented in its protected form by Formula IV: 
 
       
         
           
           
               
               
           
         
       
       wherein the fluorophore is dissolved in, embedded in, affixed in, absorbed in, or suspended in the matrix material and forms a fluorescent complex when bound in its unprotected form to Pb 2+ . 
     
     
       10. The Pb 2+  sensor of  claim 9 , wherein the matrix comprises a material selected from the group consisting of an aqueous solvent, a gel, a sol-gel material, a solvent, a paper, a polymer, a nanoparticle, a solid state material, and a surface modified material. 
     
     
       11. The Pb 2+  sensor of  claim 9 , further comprising a device capable of measuring an intensity of a fluorescence emission spectrum. 
     
     
       12. The Pb 2+  sensor of  claim 9 , wherein one or more of the hydrogens on the fluorophore is replaced with a group reactive with a functionality in the matrix material. 
     
     
       13. A method of detecting Pb 2+  comprising:
 contacting a Pb 2+  sensor comprising a fluorophore represented in its protected form by Formula IV: 
 
       
         
           
           
               
               
           
         
       
       with a composition, wherein Pb 2+  in the composition binds with the fluorophore in its unprotected form to form a complex; and
 measuring a fluorescence emission intensity of the complex. 
 
     
     
       14. The method of  claim 13 , wherein the method selectively detects Pb 2+  in the presence of other metal ions. 
     
     
       15. The method of  claim 14 , wherein the fluorescence emission intensity of the complex formed with Pb 2+  is greater than the fluorescence emission intensity of a complex formed from the fluorophore binding with another metal. 
     
     
       16. The method of  claim 13 , further comprising:
 calculating a concentration of Pb 2+  ions in the composition based on the fluorescence emission intensity of the complex. 
 
     
     
       17. The method of  claim 13 , wherein the composition is an aqueous composition. 
     
     
       18. The method of  claim 17 , wherein the aqueous composition is selected from a drinking water sample, a ground water sample, a sample from a body of water, a paint chip extraction, an environmental sample, a soil extraction, a biological fluid sample, a food sample extraction, and an air sample. 
     
     
       19. The method of  claim 13 , wherein the Pb 2+  sensor further comprises a matrix material selected from the group consisting of an aqueous solvent, a gel, a sol-gel material, a solvent, a paper, a polymer, a nanoparticle, a solid state material, and a surface modified material, and
 the fluorophore is dissolved in, embedded in, affixed in, absorbed in, or suspended in the matrix material.